1. Field of the Invention
The present invention relates to an apparatus and method for driving a plasma display panel. More specifically, the present invention relates to a driver circuit for plasma display panels.
2. Background Description
In recent years, flat panel displays such as liquid crystal displays (LCD), field emission displays (FED), plasma display panels (PDP), and the like have been actively developed. The PDP is advantageous over other flat panel displays in regard to its high luminance, high luminous efficiency, and wide viewing angle, and accordingly, it is favorable for making a large-scale screen bigger than 40 inches as a substitute for the conventional cathode ray tube (CRT).
The PDP is a flat panel display that uses plasma generated by gas discharge to display characters or images, and it includes, according to its size, more than several scores to millions of pixels arranged in a matrix pattern. Such a PDP is classified into a direct current (DC) type and an alternating current (AC) type according to its discharge cell structure and the waveform of the driving voltage.
The DC PDP has electrodes exposed to a discharge space to allow a DC to flow through the discharge space when voltage is applied. This requires a resistance for limiting the current. In contrast, the AC PDP has electrodes covered with a dielectric layer that naturally form a capacitance component to limit the current and to protect the electrodes from the impact of ions during discharge. This is superior to the DC PDP in terms of longevity.
Typically, the driving method of the AC PDP comprises a reset (initialization) step, an addressing (write) step, a sustain discharge step, and an erase step.
In the reset step, each cell is initialized in order to readily perform a subsequent addressing operation on the cell. In the write step, wall charges are formed on selected “on”-state cells (i.e., addressed cells) in the panel. In the sustain step, a discharge occurs to actually display an image on the addressed cells. In the erase step, the wall charges on the cells are erased to end the sustain discharge.
In the AC PDP, the panel between address electrodes, sustain electrodes, and scan electrodes acts as a capacitance load and is therefore called a panel capacitor. Due to the capacitance of the panel capacitor, reactive power is necessary in order to apply a waveform for addressing or sustain discharge. A circuit for recovering the reactive power and reusing it is called a “power recovery circuit”, some of which are suggested by L. F. Weber in U.S. Pat. Nos. 4,866,349 and 5,081,400.
In conventional power recovery circuits, however, 100% energy recovery is impossible due to turn-on loss of switches and loss due to the circuit itself, such as switching loss during the recovery process. Accordingly, the address voltage and the sustain discharge voltage cannot be changed to a desired voltage using switches performing hard switching that cause a loss of power. Moreover, the rise/fall time of the address voltage is increased in order to reduce the addressing speed.